Mutation driver: ligand-independent constitutive amplifications of signaling owing to deactivating mutations in patched receptor (Ptch1) or SUFU [194, 195], invoking mutations in Smo [196] (i.e., BCC [197, 198], subtyped medulloblastoma [199], rhabdomyosarcoma [200]). This evidence concerns the gene SMO and skin basal cell carcinoma.